Serpina1 encodes alpha-1-antitrypsin which predominantly complexes with and inhibits the activity of neutrophil elastase produced by hepatocytes, mononuclear monocytes, alveolar macrophages, enterocytes, and myeloid cells. Subjects having variations in one or both copies of the Serpina1 gene may suffer from alpha-1-antitrypsin deficiency and are at risk of developing pulmonary emphysema and/or chronic liver disease due to greater than normal elastase activity in the lungs and liver.
In affected subjects, the deficiency in alpha-1-antitrypsin is a deficiency of wild-type, functional alpha-1-antitrypsin. In some cases, a subject having a variation in one or both copies of the Serpina1 gene is carrying a null allele. In other cases, a subject having a variation in one or both copies of the Serpina1 gene is carrying a deficient allele.
For example, a subject having a deficient allele of Serpina1, such as the PIZ allele, may be producing misfolded proteins which cannot be properly transported from the site of synthesis to the site of action within the body. Such subjects are typically at risk of developing lung and/or liver disease. Subjects having a Serpina1 null allele, such as the PINULL(Granite Falls), are typically only at risk of developing lung disease.
Liver disease resulting from alpha-1 antitrypsin deficiency is the result of variant forms of alpha-1-antitypsin produced in liver cells which misfold and are, thus, not readily transported out of the cells. This leads to a buildup of misfolded protein in the liver cells and can cause one or more diseases or disorders of the liver including, but not limited to, chronic liver disease, liver inflammation, cirrhosis, liver fibrosis, and/or hepatocellular carcinoma.
There are currently very limited options for the treatment of patients with liver disease arising from alpha-1-antitrypsin deficiency, including hepatitis vaccination, supportive care, and avoidance of injurious agents (e.g., alcohol and NSAIDs). Although replacement alpha-1-antitrypsin therapy is available, such treatment has no impact liver disease in these subjects and, although liver transplantation may be effective, it is a difficult, expensive and risky procedure and liver organs are not readily available.
Accordingly, there is a need in the art for effective treatments for Serpina1-associated diseases, such as a chronic liver disease, liver inflammation, cirrhosis, liver fibrosis, and/or hepatocellular carcinoma.